The dangers of operating a motor vehicle at high speeds have been well documented by the high number of accidents causing both injuries and fatalities by operators, passengers, and sometimes even bystanders. Often times, the severity of the accident can be substantially reduced if the speed of the vehicles can be adequately controlled. It is now desirable to create an Adaptive Motor Vehicle Governing (AMVG) System to improve the safety of roadways. The AMVG System may be used to regulate the speed of motor vehicles to ensure compliance with established speed limits. Direct control, easy installation and manageable maintenance make the AMVG System an extremely viable solution to the growing problem of speed related accidents. Other embodiments of the AMVG System allow the transmission of other types of information to a motor vehicle moving at a high rate of speed.
The use of RFID as an enabling technology effectively addresses the issue of direct control. RFID is an automatic identification method and relies on storing and remotely retrieving data using a device called an RFID tag or transponder, which is a small object that can be attached to, or incorporated into, an object. RFID transponders contain silicon chips and antennas that enable them to receive and respond to radio-frequency queries from an RFID reader. Identification is performed almost instantly (within milliseconds). Additionally, identification does not require contact or a direct line of sight. Similarly, passive RFID transponders require no internal power source and run off of induction, whereas active RFID transponders require a power source. The RFID transponders store unique information and serve as a portable data carrier.
Generally, the process begins when a passive battery-less RFID transponder is charged through induction from the RFID antenna's magnetic field. The RFID antenna is the part of the system that radiates the induced magnetic field energy to, and receives information from, the RFID transponder. A magnetic field is generated by the RFID reader's RFID antenna and charges a capacitor in the RFID transponder. The RFID reader cycles between creating a magnetic field to charge an RFID transponder through induction and listening for a radio signal back from the RFID transponder. This cycle is continuous and allows the RFID reader to communicate with RFID transponders placed within the RFID antenna's read range without being queued. Once the RFID transponder stops receiving power through induction and its capacitor is fully charged, it sends its programmed information to the RFID reader. This information is deciphered by the RFID reader and documented according to a specified application.
Others have proposed using road-side RFID transponders with RFID readers located in each vehicle. There are several problems with this implementation. There are three frequency ranges used for RFID; Ultra High Frequency (UHF), High Frequency (HF) and Low Frequency (LF). Radio signals are electromagnetic waves and have a magnetic component and an electric component. LF and HF systems use the magnetic field to transfer power by induction. This field has a well-defined zone, but the strength of the field falls off quickly. UHF systems use the electric field to transfer power by capacitive coupling. The strength of this field does not fall off as quickly, so potentially longer read distances are possible. Reflection means that the zone is less well defined. As a result, UHF has the potential for the largest read range but has the least potential to penetrate through materials. Conversely, LF has the potential for the smallest read range but has the greatest potential to penetrate through materials. HF falls in the middle of these two extremes. Thus, on a multi-lane highway, a road-side reader would have difficulty reaching vehicles in the middle or opposing lanes.
Further, the presence of metal can present a variety of interference issues with RFID systems. Obviously, the primary material used to construct vehicles is metal, and there is a large presence of this on public roadways. Water, in its various phases, can also pose transmission issues with UHF and HF RFID systems. Thus, signals can easily be disrupted during rain, snow, or hail as well.
These factors, combined with the high speed of travel along many roadways, present several unsolved issues for an RFID speed control system. The embodiments of the AMVG System described herein provide a number of new advantages. The embodiments herein provide a high powered RFID antenna attached to an object, to ensure accurate transmission of authenticated information to an RFID reader, without interference from other active RFID devices within close proximity, when an RFID reader/RFID antenna pass in close proximity of RFID transponder(s) at high rates of speed. In this exemplary embodiment LF RFID is preferred.